Heat detector



FIG. 1 is a perspective view of a heat detector showing my new design. The broken lines depict unclaimed environmental subject matter.

FIG. 2 is a top view thereof.

FIG. 3 is a side view thereof.

FIG. 4 is an end view thereof; and,

FIG. 5 is a bottom view thereof.

In the drawings, the broken line showing of elements of the heat detector, including the base depicts environmental subject matter and forms no part of the claim. The dot-dash-dot lines disclose the boundary between the central heat detector element and the base. 

CLAIM The ornamental design for a heat detector, as shown and described. 